The most common and most likely answer to this crossword clue is the 6 letter word GASKET
I've seen this crossword clue in The Sunday Telegraph
G
A
S
K
E
T
More clues leading to the result GASKET
- Put request in to obtain seal
- Come by bearing request for seal
- Engine component to buy, with request for installation
- Close to rock, gets to swim with a seal
- Manage to file request for compressible ring
- Request put in to obtain spare part for car
- Fuel kept without pressure seal
- Blow it, you must be mad!
- Take over request for engineering part
- Seal petition in bag
Buddy explains!

The straight part
We know that "Seal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case seal = gasket.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GASKET mean?
GASKET noun- A length of rope used for reefing a sail, or holding a stowed sail in place.
- Any mechanical seal that serves to fill the space between two objects, generally to prevent leakage between the two objects while under compression.
- A material which may be clamped between faces and acts as a static seal. Gaskets may be cut, formed, or molded to the desired configuration.
- Any of a wide variety of seals or packings used between matched machine parts or around pipe joints to prevent the escape of a gas or fluid.